Turkey has accused the United States of dragging its feet over the creation of a buffer zone in northern Syria intended to prevent conflict between Turkish and pro-Kurdish forces in the country.

Turkey's foreign minister, Mevlut Cavusoglu, told reporters in Ankara on Tuesday that there had been "only cosmetic" steps taken in establishing the buffer zone.

"There have been some joint patrols, yes, but steps taken beyond that... are only cosmetic," he said.

NATO allies Turkey and the US agreed last month to set up the buffer zone in Syria to keep Kurdish forces away from the Turkish border, launching joint patrols in the area on Sunday. The Syrian government has condemned the patrols as a violation of sovereignty and international law.

The safe zone is intended to create a buffer between Turkey and Syrian areas controlled by the Kurdish People's Protection Units (YPG).

Ankara regards the YPG as a "terrorist" offshoot of the Kurdistan Workers Party (PKK), a group that has fought a guerilla war with Turkey since 1984.

However, Washington sees the YPG as a crucial ally against the Islamic State group.

Cavusoglu warned the US against any delay in removing YPG positions from the border area, referring to previous warnings that it is prepared to launch unilateral operations against the group.

Turkey is worried about a repeat of the Manbij deal it struck with the US last year.

The two countries agreed a road map in May 2018 to clear the YPG from Manbij in northern Syria, but Turkey says the withdrawal never happened as agreed.

Deputy commanders from the US Central Command and US European Command were due to meet their Turkish counterparts on Tuesday, Turkey's defence ministry said on Twitter.

The military officials were due to discuss "future support" for the joint US-Turkey operations centre in southeast Turkey and other "key activities", CENTCOM said in a statement.

Hande Firat, a Hurriyet daily columnist, wrote on Tuesday that Turkish officials wanted a 440-kilometre zone along the border, and were unimpressed that the first stage of the agreement only covered a 120-kilometre area.

Firat added that Sunday's joint patrols were "just for show" on the part of the Americans, and that Turkish soldiers wanted to go far deeper into Syria than the five-kilometre area that they covered.

The Syrian government condemned the joint US-Turkish patrols as a “flagrant violation of international law”.

“The Syrian Arab Republic condemns in the strongest terms the launching of joint patrols by the US administration and the Turkish regime in the Syrian al-Jazeera region as a flagrant violation of international law and the sovereignty and territorial integrity of the Syrian Arab Republic,” a Syrian Foreign Ministry official said on Sunday, according to state news agency SANA.

The issue was due to be discussed between Turkish President Recep Tayyip Erdogan and US counterpart Donald Trump later this month on the margins of the UN General Assembly.